It looked like nutsedge, but didn't really seem triangular to me. I didn't spray anything on them and just pulled what I could, but really didn't have much time to mess with it. I let a patch grow and it got a lot bigger than any nutsedge that i was dealing with last summer. I also thought nutsedge was a hot weather weed. In the meantime I've been mowing low with my reel mower (3rd notch from the top on Tru-Cut c27 so still high for reel mower but much lower than rotary) and went to flower and it's definately poa annua.. I don't think it's Poa Trivialis because this, http://www.agry.purdue.edu/turf/pubs/agry-98-02.pdf, says Poa Trivialis seldom develops seed heads when cut low and I'm seeing seed heads/flowers on the Poa 1" high grass clusters. It's also in the areas where I didn't do the pre-emergent. I thought Poa was a winter grass though, so it's weird to see it sprout now that it got warmer.